This is a c++ solution for 1brc. In this challenge you are supposed to read a file with unordered weather data, parse and do some calculations on it.
My solution is fast enough for me, I did not have the motivation to benchmark against other solutions.
My theory was that loading the file was going to be the bottleneck.
After changing to multithreaded file loading i lowered the loading time from around
1238ms to around 900ms.
Sorting the result is what takes up the majority of the rest of the time.
I have one unordered_map per thread. Those then get merged in the end in the main thread (that seems to be fast).
If I would like to do some improvements it would be to replace std::unordered_map with something faster.
I landed on around 3775ms
on my AMD Ryzen 9 5950X 16-Core Processor with 32 threads.
It's fast enogh for me to stop thinking about the problem any more.